Do black holes really evaporate — and how do we know?

In 1974, Stephen Hawking put forward an intriguing idea: Using the principles of quantum physics, he predicted that even though nothing is supposed to escape a black hole’s event horizon, these cosmic beasts can actually emit particles. And by ejecting these particles, black holes will shrink over a very long time, eventually evaporate and possibly explode.

Hawking sparked a debate that has…